Papers by Keyword: Compression Molding

Abstract: Plastic foam is widely used in varying industries due to its light weight, high strength, and good heat insulation. However, most plastic foams are produced from petroleum-based polymers which cannot be naturally degraded and can release aromatic pollution to the environment when they are molten or burned. Therefore, poly(butylene succinate) (PBS) and KMnO₄-treated spent coffee grounds (SCG), which are biopolymer and bio-filler, are used to prepare the bio-composite foam in this research by using azodicarbonamide (ACDA) as a chemical blowing agent. The 10, 20, and 30 phr of the treated SCG and the 6 and 10 wt% of blowing agent are compounded with PBS resin using a two-roll mill and foamed by compression molding machine to investigate the possibility of the batch foam production. All bio-composite foams are investigated for both physical and mechanical properties including morphology, compressive strength, abrasion resistance, bulk density, and water absorption. All foams were successfully prepared by a two-step technique in compression molding to melt the compounded PBS pellets first at 160°C, 90 bar and then decompose the ADCA blowing agent to generate foam cells at 200°C, 120 bar. The appearance and morphology of the obtained foams showed that the cells were smaller and more even distribution with the treated SCG addition. The compressive and abrasion resistant properties decreased as the treated SCG increasing, excepted the bio-composite foam with 30 phr of the treated SCG. whereas the addition of ADCA showed an ambiguous trend. Both filler and blowing agent contents caused a somewhat decrease bulk density and increase water absorption.

Abstract: The further development of in-mold-assembly (IMA) technologies for structural hybrid components is of great importance for increasing the economic efficiency and thus the application potential. This paper presents an innovative IMA process concept for the manufacturing of bending loaded hybrid components consisting of two outer metal belts and an inner core structure made of glass mat reinforced thermoplastic (GMT). In this process, the core structure, which is provided with stiffening ribs and functional elements, is formed and joined to two metal belts in one single step. For experimental validation of the concept, the development of a prototypic molding tool and the manufacturing of hybrid beams including process parameters are described. Three-point bending tests and optical measurement technologies are used to characterize the failure behavior and mechanical properties of the produced hybrid beams. It was found that the innovative IMA process enables the manufacturing of hybrid components with high energy absorption and low weight in one step. The mass-specific energy absorption is increased by 693 % compared to pure GMT beams.

Abstract: Disposable face masks which are used to prevent the massive spreading of Covid-19 infection, will be new plastic wastes, causing environmental problems. The purpose of this study was to investigate the potential processability of recycling disposable masks, composing of structural layers of nonwoven polyolefin fabrics by compression molding and grinding before melt recycling. It was found that the disposable masks used in this research, composed of 3 layers of polypropylene nonwoven with different fabrication methods but they had a similar melting temperature (T_m) thus provided the possibility of melt processing after removing accessories such as rubber strap and metal wire. The compressed mask sheets made from 1, 3 and 10-stacking sheets of disposable masks were subjected to the grinding analysis by ImageJ program to investigate the particle size distribution. Mechanical and physical properties as well as morphology study of the compressed mask sheets were further analyzed. The tensile strength and elongation at break of compressed mask sheets in horizontal direction were higher than that of the compress mask sheets by vertical direction due to a folding pattern of the disposable masks. The fracture surface of the compressed mask sheets was hard and brittle thus they were suitable for grinding process. Image analysis histogram showed that the grinding condition of 5 minute-cutting time of the compressed 10-stacking mask sheets provided smaller and uniform particles while the 1-stacking mask sheets had larger particle size after grinding due to their thinness which causes them slip through cutting blade. Grinded compressed masks had potential recyclability for melt blending with neat polypropylene at various blending ratios.

Abstract: This paper presents the results of the study of the effect of polymer materials compression and injection methods of molding on the physical and mechanical properties of the resulting samples. Widely used polymers such as poly-amide, thermoplastic elastomer and polyketone were taken as the objects of study. Granite composites based on polyamide were produced by PolyLab Rheomex RTW 16 twin-screw extruder, then modified with fine powders of schungite, graphite and silicon dioxide. Samples for testing in the form of double-sided blades were obtained by injection molding on a Babyplast 6/10V machine and compression molding on a Gibitre hydraulic press. Elastic-strength tests of the obtained samples were carried out on a tensile testing machine UAI-7000 M.

Abstract: The effect of polyketone thermal processing duration on the rheological properties of the melts and the physical and mechanical characteristics of the samples, obtained by injection and compression molding methods, is studied.

Abstract: It has been presented the study results of the firing process of cellular ceramics from granulated foam glass. The chemical, mineral and granulometric compositions of the raw materials are given. It has been shown the characteristic of ceramic-technological properties of raw materials. The samples were burned from the granulated mixture in the temperature range of 850-1000 ° C. It has been established the change dependence in the physicomechanical properties of cellular ceramic samples on the temperature and firing duration. The results of the study of the macro-and microstructure of cellular ceramics are given. It has been revealed the effect of intensive formation of the pyroplastic phase and the connection between small pores at a temperature of more than 950 ° C. After the enlargement, the cells leave the three-phase ceramic system and it was the increase in the average density of cellular ceramics is 1.4-1.5 times. The influence of a solid glass-ceramic shell along the inner surface of the pores on the decrease in water absorption of cellular ceramics to 6.5-7% is established.

Abstract: Jute fabrics reinforced Polypropylene (PP) matrix composite was fabricated by compression molding and Unsaturated Polyester Resin (UPR) matrix composites were also fabricated by hand lay-up technique. The fiber content of the composites was 40% by weight. Mechanical properties between two types of composites were compared. Tensile Strength (TS), Tensile Modulus (TM), Elongation at break (Eb%) , and Impact Strength (IS) of the jute fabrics/PP composites were found to be 47 MPa, 1.2 GPa, 13% and 8 kg/cm, respectively. On the other hand, TS, TM, Eb%, and IS of the jute fabrics/UPR composite were found to be 43 MPa, 1.3 GPa, 10% and 6 kg/cm, respectively. It was found that both composites showed almost similar mechanical properties. After tensile testing, fracture sides of both types of the composites were studied by Scanning Electron Microscope (SEM) and the results revealed poor fiber matrix adhesion for jute fabrics with PP and UPR. The fabricated composites became partly biodegradable because of jute (natural fiber) and mechanical properties of both types of composites showed promising results for commercial applications.

Abstract: Sugarcane bagasse fiber reinforced polypropylene (PP) based composites were prepared by compression molding. The fiber content was 40% by weight. Tensile strength (TS), tensile modulus (TM) and elongation break (Eb%) of the composites were found to be 51MPa, 1414 MPa and 14% respectively. The TS, TM and Eb% of the PP sheet were 25 MPa, 456 MPa and 76% respectively. Due to fiber reinforcement, an increase of 102% TS and 210% TM, was noticed. Water uptake test was carried out by immersing the composite sample in deionized water and it was noticed that water uptake was lower for sugarcane bagasse fiber reinforced PP composite. Transform Infrared Spectroscopy was employed for functional groups analysis of the fabricated composite.

Abstract: Current elevators are mostly designed as rope-dependent elevators. Main components in the roping system are the deflection sheaves which are conventional manufactured of grey cast iron. Due to the high weight of cast iron sheaves there is a high potential for reducing mass, especially when regarding aspects of effort, safety and ergonomics while assembly and maintenance in the elevator shaft. Within the framework of a R&D co-operation the Chemnitz University of Technology and the AMB Oberlungwitz GmbH developed a fibre-reinforced plastic sheave that comply with the requirements of lightweight design. The technological basic approach to realize that development is compression molding of glass-mat-reinforced thermoplastics (GMT). The project includes the whole development-chain, consisting of part design, tool design, process chain arrangement, parameter studies as well as validation of specimen. In the course of the project appeared a high potential for improvement of the part properties by alternative design solutions. In this context current activities are focused on multi material design methods such as combining GMT with other thermoplastic prepregs. In this manner it is possible to equip every local area with the specific properties that are required. For example the ribs of the sheave, that receive highest values of stress, can be made of materials with continuous-fibre-reinforcement while the basic part body consists of GMT, which is long-fibre-reinforced. This method also enables to avoid process influenced effects like the segregation of the fibre-matrix distribution in GMT. Additionally the input of different materials offers chances to inlay non-preheated prepreg blanks into the compression mould, so that the amount of the preheated material volume can be reduced. In this way cycle times and also lost of temperature due to transfer times of the heated blanks to the mould can be reduced.

Abstract: A facile method is introduced for production of micro-nanostructured silicone rubber surfaces by means of direct replication using a compression molding system. The fabricated samples possessing surface roughness display water contact angle of more than 160o and contact angle hysteresis (CAH) and sliding angle of less than 5o. Such low surface wettability of silicone specimens verifies the induced superhydrophobic property. Chemically etched aluminum surfaces could work excellently as templates whose patterns were replicated on the rubber surfaces successfully. Various etching conditions were examined. Surface characterization techniques revealed the presence of micro-nanostructures on the produced silicone surfaces.